Telephone system.



H. D. CURRIER.

TELEPHONE-SYSTEM .APPLICATION ,FILED OCT- 1. 1913.

L%9,6., Patented Dec. 4,1917.

HmAM '1). CURRIER,

.siding provide calling pi OF CHICAGO, ILLINOIS, ASSIGNOR T0 IIELLOGG SWITCHIBOARD AND SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A

CORPORATION or ILLINOIS.

To all whom it may concern.

Be it known that I, HIBAM D. citizen of the United States of America, re-

in Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Telephone Systems, of which the following is a specification.

My invention relates in general to telephone systems and is directed more particularly to certain features having to do with the control of supervisory, test and meter circuits, an object of my invention being to provide a simplified arrangement of control circuits of the above character in connection with an ope'rators link circuit.

One of'the features of my invention is the provision of a simplified reverting busy control circuit wherein'a supervisory relay associated with the calling end ofthe "link circuit is adapted to control the application of such a revertive test.

Another feature of my invention is the provision of a calling supervisory control circuit wherein the calling supervisory signal is combined with a calling pilot and control circuit so as to produce a more useful supervision of the connection.

In systems calling supervisory common, a

whereln lamps are provided and wherein such lamps are lighted when connection is made with the called line and remain lighted until a response is secured it is of no advantage to therewith because of the fact-that during a greater portion of the time there is some unanswered call at each operators position and therefore such a pilot signalwould remain lighted the most of-the time and serve no useful purpose. In systems wherein auto matic ringing is provided I have found it unnecessary to arrange the calling supervisory signal so that it will light during the period of ringing because of the fact that the ringing disconnect 1s automatic. Therefore I have arranged the present embodiment of -my invention so that the calling supervisory signal does. not show during the ringing period but when a called subscriber replaces his receiver after finishing his conversation, the calling supervisory signal will light. I have also provided means wherebycwhen a calling plug is inserted into a jack of a called line, the calling supervisory signal will light and remain lighted until the ringing key is Specification of Letters Patent.

ot signals in connection Patented Dec. 4, 191?.

Application filed October 1, 1913. Serial No. 792,747.

depressed. The period between inserting the plugin the called jack and the operation of the ringing key, hanging up of the called receiver until the calling plug is withdrawn, are periods where an operator may lose considerable time in handling connections and therefore I have provided a' common calling pilot signal associated with the calling supervlsory signals of each operators cord circuits whereby a chief operator or monitor is enabled to see by the operation of the calling pilot signal just how each operator is Working during the said periods.

For a better understanding of my invention reference is to be had to the accompanying drawing in which two telephone lines L and L are shown, the party line type and having a plurality of substations A or'A connected thereto. Said lines terminate at a central oflice switchboard in line circuits comprising jacks and line signal control apparatus preferably a line relay LR, cut-off relay CO.

I have preferably embodied my invention in an operators cord circuit B having answering and calling plugs 1 and 2 respectively, said plugs being united-by the heavily marked tip and sleeve conductors having interposed condensers 3, 4. An answering supervisory relay AS is associated with the answering end of the cord circuit together with a switching relay SW which assists in the control of the answering supervisory signal 5, and also connects the operators telephone 0 to the cord circuit. An answering pilot relay AP is also provided.

In connection with the calling end of the cord circuit, I provide supervisory control relays comprising a calling supervisory re lay CS and a so-called switching relay SW which relay SW assists in the control of the calling supervisory signal 6 and disconnects the operators telephone 0 from the cord circuit. Automatic ringing control apparatus is also provided including an interrupter relay IR which is adapted to periodically apply ringing current to the called line, and

and the period from the each line being of and the lighting of line lamp '14 are operated independently operable ringing contacts, 7,

9 and '10 and a set of common contacts 11, 12. The ringing key is also preferably of the so-called indicating type in which when a ringing plunger is fully depressed to its ringing position, one of the ringing contacts is operated as are also the 11, 12. When the operator relieves the pressure upon-the actuated ringing plunger it restores to its middle or indicating position restoring the common contacts'll, 12 to their normal position as illustrated, but maintainen the operator inserts the" calling plug into'a jack j, the calling supervisory signal 6 and its associated and remain so until-the ringing key is actuated at which time the ringing control relay RC perates to efiace signals 6, l3, 14. The actuation of the ringing key is also effective to cause the ener-' gization of the meter relay MR to re 'ster a single connection upon the meter although the operator may repeatedly operate the ringing key, further registrations of the meter apparatus is prevented, until anher connection by the cord circuit B is established, or such additional registration cannot occur without calling some party on t e line connected with.

n connectionwith party linesystems it is most essential that a so-called revertive busy test be provided so that an operator may know when a subscriber is calling for a substation on his own line. To this end I have provided'an improved revertive busy 1 control so arranged that when the operator places the tip of the calling plug 2 upon the sleeve of a busy jack, the calling supervisory relay CS will operate and connect the revertive busy tone R to a contact of the answering plug 1 whereby if the calling plu 2 istouchlng a jack multiply connected to the jack in which the answering plug 1 is inserted, a, characteristic busy tone is transmitted to the operators telephone.

av-ing described more in ment of myjinvention, its operation in the course of estabhshlng a connect on Wlll now be described. Assuming that a substation on line L desires to call, e receiver thereat is removed whereby a circuit for the line relay R is established over the calling line, causing the energization of saidrelay 16. The'operator 1n response to this signal inserts an answering plug 1 into the answering jack J of the calling line whereby a series circuit including the winding of cut-oil rela CO and switching relay SW is estab ished through the third contacts of the connected plug and jack. Said are therefore energized, the'energization of common contacts I plug 1, the

pilot signals 13,

.' plug 2 lnto a jack "lished, but this s only relays CO and SW .lay and eti'acing the line lamp. Responsive to the energization of relay SW, its alternate contacts 17, 18 are closed connecting the operators telephone 0 over conductors 19, 20, and normal contacts 21, 22 in bridge of the talking strands of the cord circuit. Also upon connection of jack J and answering supervisory relay AS 1s connected in bridge of the calling line L whereby current flows through the winding of said relayand over the calling line, causing the energization of AS.

e operators telephone having been automatically connected with the link circuit, the operator ascertains the wants of calling subscriber and finding that a connection is wanted with substation A of the line L, the operator proceeds to test the called line in the usual manner, that is by touching the tip ofthe calling plug 2 to the third or test contact of the called "line jack j. Finding the called line is idle she inserts 7' thereof; A circuit includlng switching relay SW and cut-ofi relay, CO isthere fore established over the third contacts of the connected plug and jack 2, j respectivelywhereby said relays .are energized. The energization of CO is placed against this third contact testing, an energizing circuit through of relay CS is estabincldental when a line different than the calling line is being tested, and has no elfect upon the usual click test circuit here employed.

eferring again to the switching relay SVV also responsive to itsenergization its alternate contact 26 is closed whereby ground is connected to conductor 27 normal contact 28 of relay CS, supervisory signal 6 and the winding of the calling pilot relay GP to battery. Lamp 1 the upper ey is operated. It will be apparent that with this arrangement a chief operator or monitor by watching any operators pilot signals 13 or 14 can tell how the operator is working. he operators pilot 13 is of course positioned before the operator, and pilot 14 may be positioned before a chief operator or monitor. r

. e operator now depresses the plunger of the proper ringing key 7, 8, 9 or 10 to its fully depressed position, thereby actuating the associated ringing contacts and the common contacts 11, 12. ing of alternate contact 12, a circuit for the meter relay MR is established from battery through the winding of MR, alternate contact 12, to grounded normal contact 29 whereby said relay MR is energized to cause a single operation of the meter M by its magnet 30. Responsive to the closing of alternate contact 11, which occurs after the closing of alternate contact 12, a circuit for the ringing control relay RC is established, traced from battery through the winding of RC, alternate contact 11 to the grounded conductor 27 Relay RC therefore interrupts its normal contact 29 efl'acing signals ringing current 6, 13, 14 and restoring the meter relay MR. Relay RC also establishes a locking circuit for itself through its alternate contact 29, normal contact 28 to grounded conductor 27 which circuit s maintained until the calling supervisory relay CS is energized by the response of thecalled subscriber. The operator of course releases the key plunger after maintaining it fully actuated for a short period, whereby the common contacts 11,12 are again restored to normal, but the actuated ringing co tact 7 8, 9, or

10 is maintained closed in its alternate position. It will be apparent that although the operator may actuate the ringing plunger more than once, further operations of the meter relay MR are prevented due to the interruption of its circuit at normal contact 29 of RC.

Responsive to the closing of alternate contact 31 of RC, and upon the closing of normal contact 11 of the ringing key, a circuit for the interrupter relay IR is established traced from battery through interrupter 32, the winding of IR, alternate contact 31, normal contact 11, to grounded conductor 27. Relay IR is therefore periodically energized operating its contacts 33, 3 1 each closure of the alternate contacts 33, 34, connecting from the proper ringing generator in bridge of the called line to rin the call bell eac closure of normal contacts 33, 34, of relay IR, the calling supervisory relay CS is connected in bridge of the called line but due to the condenser at substation A no path for the flow of direct current over CS exists as long as the receiver remains upon the switch-hook. During the ringing period normal contacts 35, 36, of relay RC are interrupted so that the ringing current does not afiect the calling line.

In response to the operation of the call bell at substation A the subscriber thereat removes his receiver whereby a path for direct current is established over the called line L and including the windings of calling supervisory relay CS. Said relay there- Responsive to the dos-- actuated ringing this results in the and CO Signal of substation A Upon.

fore energizes interrupting its normal contact 28 and thereby interrupting the locking circuit for the ringing control relay RC, causing its denergization Alternate contact 31.0f RC is therefore interrupted, in-

terrupting the circuit for relay IR and preis again connected to normal contact 29 of RC whereby signals 6, 13, and 14 are again lighted, and remain lighted until the calling plug 2 is withdrawn from the jack, thus affording to the chief opera-tor ormonitor before whom lamp 14 is positioned, a check upon the period of disconnection.

Should the operator now attempt to cause another, or improper actuation of the meter relay MR by again actuating the ringing key RK before withdrawing plug 2, the result will be that ringing current will again be applied to the connected line as before de scribed. It will be apparent from the above that itis impossible for the operator to register connections on the meter without calling some substation;

The operator observing the lighting of signals 5, 6 referred to, is aware that disconnection is desired and therefore withdraws plugs 1, 2 from the connected jacks, At the answering end of the cord circuit restoration of relays CO and SW, and at the calling end of the cord this results in the restoration of relays SW 5 is therefore eifaced due to the interruption of alternate contact 24 of SW, and the signals 6, 13, 14 are eifaced tablishing the connection beingagain at normal is available connections.

Now as to the operation of so-called refor use in establishing other 'verting busy test, assuming that an answering plug 1 has been inserted into a jack J in response to a call over line L and whereby relays AS and SW have operated as before, and that the calling substation is to be connected with another substation on the same line. Therefore the operator, unaware that the calling and called substations are on the same line will place the tip of the associated calling plug 2 against the thirddso phone line having multiplejacks, an operthe jacks J a circuit isestablished for relay withdrawal of th restoration of t S from battery at said'test contact of J, the tip of plug 2; tip calling conductor, nor-' mal contact 33 and the upper winding of telephone 0, alternate contact 17, conductor normal contacts 21,36, 34, and-the lower winding of OS to battery and ground. The haracteristic tone knows ment or. two while the called substation is eing rung.

The operator now inserts the calling plug 2 into a multiple jack J whereby the switchingrelay SW is operated in a manner as before described.

e wanted substation in a manner as before described. The apenergization of CS causing the disconnection of ringing current in a manner as atready described.

' hen the subscribers have finished their conversation and upon the replacing of both receivers upon their switch-hooks, relays AS and CS denergize resulting in the oper- 1 ation of the signals for disconnection in a manner as before described followed by the e connecting plugs and the he apparatus to normal. aving described my invention, what I now claim as new and desire to secure by United States Letters Patent, is:

l. A telephone system comprising a telejacks, means for rendering the other jacks connected thereto busy, a double wound supervisory relay connected to the callin end of the link circuit, a signal controlled t ereby, a characteristic test tone, an operators" to said operators telephone; 1 i

i a cal theflmk c1r cu1t, a signal controlled thereby,

operators telephone, and

and means whereby when the calling terminal of said link circuit is. placed against multiplefjacklof. said line said relay. iszenergized to transm'itsaidtest tone 2. A telephone system compr -a telephone line having multlple ack's, an. operators link circuit, means for-connecting the answering end of sa d link cu-cuit to one led line connected to the call to connect said test tone in circuit'with said ks are rendered busy, a calling superthe cal controlled thereby, a characteristic test tone, an operators tele hone, means for rendering the jacks of said lines busy, means for energizing said relay when the calling tip lines, means whereby when said tip terminal is placed against a I calling line said relay is energized to connect saidtest toneln' c rcuit with said oper.

ling end of said link circuit, a signal he connected cu1t, a s1gnal controlled thereby, a char- 'acterlst c test I g one of said lines whereby the other connect- 7 phone lines,

tlif' to again operate said signal,

5. A telephone system comprising telephone lines, an operators link circuit, a

supervisory signal, means responsive to con-. nection of sald link clrcuit to a called one of said lines to operate said signal, a ring-.2

in key for applying ringing current to the ca led line, means responsive to the, actuation of said key to eflace said signal, and.

substation controlled means for re-operating said signal.

6. A telephone system comprising telephone lines, an operators link circuit, a supervisory signal, means responsive to connection of said link circuit to a called one of said lines to'operate said signal, a ringing key for applying ringing current to the called line, means responsive to the actuation of said key to efface said signal, and means responsive to the replacing of the receiver at the called substation after said call has been answered to again operate said signal.

7 A telephone system comprising telephone lines, an operators link circuit, a

supervisory signal, means responsive to conlink circuit to a called one I nection of said of said lines to operate said signal, a ringing key for applying ringing current to the called line, means responsive to the actuation of said key to eflace said signal, means responsive to the replacing of the receiver at the called substation after said call has been answered to again operate said signal,- and means whereby'when said link circuit is d sconnected from the called l1ne said s1gnal is again effaced.

8. A telephone system comprising telean operators link circuit, a supervisory signal, means for connecting said link circuit to a called one of said lines, means for applying ringing current to the called line, circuit connections for said signal effective to operate same prior to the application of said ringing current, means effectlve when said ringing current is applied to efi'ace said signal, and a relay for rendering said circuit connections efiective to reoperate said signal.

9. A telephone system comprising telephone lines, an operators link circuit, a supervisory signal, means for connecting said link circuit to a called one of said lines, means for applying ringing current to the called line, circuit connections for said signal efiecti've to operate same prior to the application of said ringing current, means effective when said to eftace'said signal, and means responsive to the replacing of the receiver at the called substation after said call has been answered a substation on said line,

ringing current is applied 10. A telephone system comprising telephone lines, an operators link circuit, means for connecting said link circuit to a calledone of said lines, means for thereafter signaling a substation on said line, and a pilot or supervisory signal positioned before a distant operator whereby the periods of time between the connecting to and the sig naling of a called substation and the receiving of a disconnect signal from and the actual disconnection from tion, are indicated.

11. A telephone system comprising telephone lines, an operators link circuit, means for connecting said link circuit to a called one of said lines, means for signaling a disconnect signal, and a pilot or supervisory signal positioned before a distant operator whereby the periods of time between the connecting to and the signaling of a called substation,

and the operation of said disconnect signal and the disconnectionof the associated plug from the line, are indicated. 7

12. A telephone system comprising tele phone lines, an operators link circuit, means for'connecting said link circuit to a called one of said lines, means for thereafter applying ringing current to said line, a disconnect signal responsive to the replacing of the receiver at the called substation after said call has been answered, and a pilot or supervisory signal positioned before a distant operator whereby the period of time between the connecting to and the ringing of a called substation, and the period of time between the operation of the disconnect signal and the disconnection of the associated lug from the line, are indicated.

13. A telephone system comprising telephone lines an operators link circuit, a supervisory signal, means responsive to connection of said link circuit to a called one of said lines to operate said signal, a ringing key for applying ringing current to the called line, means responsive to the actuation of the said key to efiacesaid signal, means for restoring said last means'without again operating said signal, subscriber controlled means for reoperating said signal, and operator controlled means for again efiacing said signal.

14:- ln a telephone system including a subscribers telephone line, a plug-ended link circuit, a supervisory signal for said link -circuit, ringing apparatus for signaling the substation upon said line, a relay for closing a circuit for saidsignal responsive to the connection of said link circuit to said subscribers line, a relay for opening said circuit responsive to an operation of said ringing apparatus, subscriber controlled means for restoring said last relay, and a 15. A telephone system including a subthe called substavisory signal,

circuit for connection to said scribers telephone line, an operators link ace saidsignal, substation conapparatus, means for closing a, circuit for said county of Cook Signed by me at Chicago,

presence of two and State of Illinois, in the Witnesses.

HIRAM D. CURRIER. Witnesses:

G. E. MUELLER, M. R. ROGHFORD. 

